Heat and pressure consolidated laminates are generally produced utilizing a core material comprising a plurality of phenolic resin impregnated paper sheets, a decor sheet impregnated with a melamine-formaldehyde resin and, optionally, a melamine-formaldehyde resin impregnated overlay sheet. These laminates have found world-wide success as construction materials i.e. wall panels, countertops etc., in the home and office. They can be prepared so as to function in a variety of service applications and can be produced with surfaces of high gloss, a matte finish or an embossed finish. They can be rendered post-formable with the application of heat and can be cut or worked much in the same manner as other building materials.
Although the above-described laminates have found a high degree of success over the past forty years, there is a continual need to improve the laminates and/or the method of their preparation and, accordingly, research is always on the outlook for means to achieve such improvements.
One of the properties of heat and pressure consolidated laminates for which an ongoing search for improvement is continually being conducted is the post-formability of laminates containing cores produced from phenolic resins. That is to say, post-formability is now imparted to decorative, heat and pressure consolidated laminates by using X-creped papers and/or a post-forming resin which is less than fully cured in the core of the laminate. The X-creped papers are substituted in part or in full for the kraft papers which are normally used in non-postforming laminates and, in the production of the laminates, the cure cycle employed in the laminating press is such that the resin components in the laminates are not fully cured. The undercuring of the resins reduces the laminate rigidity and enables post-forming to be effected with the application of additional heat in the area of the desired bend.
In U.S. Pat. No. 4,424,261 there is disclosed the use of hydroxyalkylmelamine modified resins in decorative laminates for the purpose of imparting post-formability to said laminates and to also eliminate the dark edge line thereof which is evident when the laminate is cut to size. In the invention disclosed in said patent, although the post-formability was somewhat increased in comparison to known laminates, there still exists a need to further improve the post-formability of said products.